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  • Writer's pictureThe Rare360 Editorial Team

Aplastic Anemia: Unravelling the Mystery of Bone Marrow Failure


In the vast realm of medical science, there are health conditions that, while rare, can have profound effects on the human body. One such condition is Aplastic Anemia, a serious disease where the body’s bone marrow fails to produce enough new blood cells. This condition typically impacts all three types of blood cells, a state known as pancytopenia, involving:

  • Red blood cells responsible for carrying oxygen (anemia)

  • White blood cells are crucial for fighting infections (neutropenia)

  • Platelets are essential for blood clotting and preventing excessive bleeding (thrombocytopenia)


Despite the reduction in the production of blood cells, those that manage to mature and circulate in the bloodstream remain normal. Aplastic anemia is linked to some cancers and cancer treatments, but it is not a type of cancer.


In the United States, between 600 and 900 people are diagnosed with aplastic anemia each yearIt is also more common in individuals of Asian descent. Studies show aplastic anemia affects 2 in 1 million people in Europe. It can affect people of any age, race, or gender, but it occurs most frequently in people in their teens and twenties and is also common among the elderly.


In this blog post, we will delve into the causes, symptoms, and treatments of Aplastic Anemia, shedding light on this rare blood disorder.

 

Decoding the Causes of Aplastic Anemia

Aplastic Anemia typically occurs when the immune system attacks the stem cells in the bone marrow, preventing it from making enough new blood cells. There are several factors that may contribute to the onset of this condition, including:

  • Autoimmune Disorders: An autoimmune disorder (such as Lupus), in which the immune system attacks healthy cells, might involve stem cells in the bone marrow.

  • Exposure to toxic chemicals: Toxic chemicals, such as those used in some pesticides and insecticides, benzene, and an ingredient in gasoline, have been linked to aplastic anemia. This type of anemia might improve if you avoid repeated exposure to the chemicals that resulted in the condition.

  • Chemotherapy or radiotherapy treatment: While these cancer-fighting therapies kill cancer cells, they can also damage healthy cells, including stem cells in bone marrow. Aplastic anemia can be a temporary side effect of these treatments.

  • Viral infection: Viral infections that affect bone marrow can play a role in the development of aplastic anemia. Viruses that have been linked to aplastic anemia include hepatitis, Epstein-Barr, cytomegalovirus (CMV), parvovirus B19 and human immunodeficiency virus (HIV).

  • Certain medications: Some medications can contribute to the onset of aplastic anemia, such as those used to treat rheumatoid arthritis and some antibiotics, including chloramphenicol, carbamazepine, felbamate, phenytoin, quinine, and phenylbutazone.

  • Pregnancy: In some cases, pregnancy can trigger aplastic anemia.

  • Inherited conditions: Experts link aplastic anemia to several inherited bone marrow failure syndromes. Inherited conditions include:

    • Fanconi anemia

    • Dyskeratosis congenit

    • Shwachman-Diamond syndrome

    • Diamond-Blackfan anemia

    • Pearson syndrome

Despite these known factors, most of the aplastic anemia cases have an unknown cause.

 

Aplastic Anemia Types and Severity

Aplastic Anemia can be classified into different types based on severity and cause:

  •  Acquired Aplastic Anemia This is the most common form of aplastic anemia, and occurs where there is often no obvious or known cause. In most cases, the body’s immune system mistakenly attacks and destroys the bone marrow cells. Based on the severity, it is further categorized as follows:

    • Very Severe Aplastic Anemia (VSAA): In patients with VSAA, the neutrophil count is less than 20 per microliter and the platelet count is less than 200 per microliter. All other blood cells count is similar to those with someone with severe aplastic anemia. The bone marrow activity is less than 30% in people suffering from VSAA.

    • Severe Aplastic Anemia (SAA): For a patient to be diagnosed with severe aplastic anemia, two of the following conditions must be met: -The neutrophil count is less than 500 cells per microliter. -The reticulocyte (young red blood cell) count is less than 20,000 per microliter. -Platelet count is less than 20,000 per microliter.

    • Non-severe Aplastic Anemia (NSAA)/Moderate Aplastic Anemia (MAA): The blood cell count is not as low as the other two types. The patient may also show few or no symptoms, and the condition may stay for a few years.

    • Idiopathic Aplastic Anemia: Approximately 70% of the diagnosed aplastic anemia have an unknown cause, referred to as idiopathic aplastic anemia.

  • Inherited Aplastic Anemia These are rare inherited conditions which may lead patients to develop aplastic anemia. The most common of these is Fanconi anemia and dyskeratosis congenita. People diagnosed with inherited aplastic anemia have higher chance of developing leukemia and other cancers. PNH is also closely linked with aplastic anemia.


Recognizing Aplastic Anemia Signs and Symptoms

Symptoms of aplastic anemia typically emerge gradually over weeks and months, making it possible for changes in your body to go unnoticed initially. However, in certain instances, individuals may experience immediate and severe symptoms. Here are some common signs and symptoms:

  • Fatigue or tiredness

  • Shortness of breath

  • Rapid or irregular heart rate

  • Pale skin

  • Frequent or prolonged infections

  • Unexplained or easy bruising, nosebleeds, bleeding gums, or prolonged bleeding from cuts

  • Dizziness, headache, and fever

  • Red or purple spots on the skin caused by bleeding under the skin

  • Enlarged liver or spleen

  • White patches in the mouth (oral thrush)

It is crucial to note that these symptoms can also be caused by health conditions other than aplastic anemia. 

 

Unravelling Aplastic Anemia: The Diagnostic Pathway

The diagnostic journey for a patient with Aplastic Anemia typically involves several steps:

  • Physical Examination The doctor will conduct a physical examination to check for physical signs of aplastic anemia, such as pale skin, rapid heart rate, and infections.

  • Blood Tests Several blood tests are conducted to diagnose the type of aplastic anemia. The healthcare practitioner may order the following tests:

    • Complete Blood Count (CBC): A complete blood count (CBC) is usually the first test to check for aplastic anemia. The test measures red blood cell, white blood cell and platelet levels. The test will show low count of all three types of cells in patients with aplastic anemia.

    • Reticulocyte Count: A reticulocyte count is also done to check for the count of young blood cells. People diagnosed with aplastic anemia will have low reticulocyte count.

    • Erythropoietin Levels (EPO): Erythropoietin is a protein made by the kidneys in response to low oxygen levels in the body.

    • Iron, Vitamin B12 and Folate levels: A low level of vitamin B12 and folate could cause dysplasia. Iron levels could be low (easily treatable with iron suppliments), or high (mainly caused by genetic conditions, and can be treated).

  • Bone Marrow Biopsy A bone marrow sample, typically obtained from the pelvic or breast bone, is a relatively straightforward 30-minute procedure. During this process, the doctor uses a hollow needle to extract some bone marrow aspirate, which is the liquid component of the bone marrow. Additionally, a solid piece of bone marrow is taken for a bone marrow biopsy. Following the extraction, the doctor examines the liquid bone marrow under a microscope and sends a sample to a lab. The bone marrow test provides insights into:

    • The cellular composition (cellularity) of your bone marrow.

    • The types and quantities of cells produced by your bone marrow.

    • Levels of iron in your bone marrow—whether increased, decreased, or within the normal range.

    • The presence of any chromosomal (DNA) abnormalities.

  •  Further Tests Once aplastic anemia is diagnosed, you might need additional tests to determine the causeThese could include genetic tests or tests for exposure to toxins or certain medications.

It’s important to note that aplastic anemia is a diagnosis of exclusion, meaning other potential causes of the symptoms must be ruled out. The diagnostic process can be complex and requires a thorough evaluation by a medical specialist.

 

Aplastic Anemia Treatment Options and Considerations

Treatment options for Aplastic Anemia depend on the severity of the condition and the patient’s age. Here are some common treatment options:

  • Blood Transfusions Although not a permanent cure, blood transfusions can temporarily relieve symptoms such as anemia, fatigue, and bleeding by increasing the amount of red blood cells or platelets or both in the blood

  • Stem Cell Transplantation For people living with severe aplastic anemia, a stem cell transplant or bone marrow transplant may be the only treatment option. This procedure involves rebuilding the bone marrow using stem cells from a compatible donor, often a sibling, and is particularly suitable for younger patients.

  • Immunosuppressive Therapy This therapy may be used for people who cannot have a stem-cell transplant or to control aplastic anemia in people who are waiting for a stem-cell transplantImmunosuppressants, such as antithymocyte globulin (ATG) and cyclosporine, suppress your body’s immune system and slow or stop damage to your bone marrow.

  • Medications Medications can include hematopoietic growth factors like Sargramostim and Filgrastim, which stimulate the production of blood cells from the bone marrowOther medications can include chelating agents to get rid of excess iron, immunosuppressants to suppress the immune system, antibiotics to prevent infections, and antineoplastic agents as a part of cancer treatment.


Potential Side Effects

The side effects of Aplastic Anemia treatments can vary between individuals, depending on the type of treatment used and how an individual responds to it. Here are some common side effects:

  • Excessive Bleeding: This can occur when the platelet count is very low (thrombocytopenic). This could lead to easy bruising and excessive bleeding.

  • Nausea and Vomiting: These can prevent individuals from eating or drinking or taking normal medications.

  • Loss of Appetite: This can occur due to nausea or changes in taste.

  • Stomach Pain: This can be a side effect of some medications.

  • Frequent Infections: When the white blood cell count is low, it can make you more prone to infections.


Despite the challenges, the prognosis for Aplastic Anemia has notably improved over the last 30 years. With immunosuppressive therapy, the 5-year survival rate ranges from 75% to 80%, with age influencing outcomes. Younger patients undergoing stem cell transplant from a matched related donor exhibit a probability of long-term survival exceeding 80%. As medical advancements continue, there is hope for enhanced treatments and improved quality of life for those grappling with Aplastic Anemia.


Conclusion

Aplastic Anemia is a rare disorder, that disrupts the body's blood cell production. While its origins are diverse, ranging from autoimmune disorders to chemical exposures and inherited conditions, the diagnostic journey involves thorough examinations and precise tests. Treatment options, from blood transfusions to stem cell transplants, highlight the complex nature of managing this disorder.


Looking forward, advancements in immunosuppressive therapy and stem cell transplants have significantly improved survival rates, offering hope to those affected. Ongoing research continues to unravel the mysteries of Aplastic Anemia, with a focus on tailored treatments and enhanced quality of life for patients.


Resources

  1. https://www.msn.com/en-us/health/condition/Aplastic-anemia/hp-Aplastic-anemia?source=conditioncdx

  2. https://www.mayoclinic.org/diseases-conditions/aplastic-anemia/symptoms-causes/syc-20355015

  3. https://my.clevelandclinic.org/health/diseases/16747-aplastic-anemia

  4. https://www.aamds.org/questions/how-many-people-are-diagnosed-aplastic-anemia-each-year

  5. https://www.aamds.org/diseases/aplastic-anemia/types

  6. https://www.theaat.org.uk/types-of-aplastic-anaemia

  7. https://www.leukaemiacare.org.uk/support-and-information/information-about-blood-cancer/blood-cancer-information/aplastic-anaemia/

  8. https://www.niddk.nih.gov/health-information/blood-diseases/aplastic-anemia-myelodysplastic-syndromes/symptoms-causes

  9. https://www.aamds.org/diseases/aplastic-anemia/diagnosis

  10. https://www.leukaemia.org.au/blood-cancer/aplastic-anaemia/treatment-side-effects/

  11. https://www.mayoclinic.org/diseases-conditions/aplastic-anemia/diagnosis-treatment/drc-20355020

  12. https://bestpractice.bmj.com/topics/en-us/96/prognosis

  13. https://www.hopkinsmedicine.org/health/conditions-and-diseases/aplastic-anemia

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